Bar code symbols are being employed in an ever-increasing number of applications, and the information requirements of such symbols are growing.
In recent years, there has been an increasing effort to encode large amounts of data into bar code symbols. New bar code symbol types, including 2d symbols such as stacked 1D and matrix symbols have become available which are specifically designed to increase the amount of data per area that can be encoded into a symbol.
In addition to utilizing new types of bar code symbols, users of bar code symbols have been printing such symbols in smaller sizes and in increasingly higher densities. The bar and space patterns of bar code symbols, whether 1D or 2D, are being printed and applied to items in increasingly finer prints.
The fine print of many bar code symbols in use today has resulted in an increase in the resolution requirements of optical reading devices which read such symbols. In the prior art, there has been suggested, in general, two approaches for addressing these increased resolution requirements.
The first approach suggested in the prior art for increasing reader resolution is to increase the pixel density of an image sensor used in an optical reader. This solution is highly effective performance-wise, but is also highly expensive. For purposes of illustrating the cost of increasing pixel density, a 1000 by 1000 pixel array sensor is currently approximately 8 times the cost of a 256 by 256 pixel array sensor. Incorporating a higher density pixel array into a reader also significantly increases data storage and data processing costs.
A second approach suggested by the prior art for increasing reader resolution is to adjust the reader optics so as to increase the magnification of captured scenes. This solution comes with the price of decreasing the area of the reader's field of view, however.
There is a need for a low cost high performance optical reader which is capable of reading fine print bar code symbols which are finding increased use.